Concentration process.



WALTER A. SCOTT, OF CHICAGO, ILLINOIS.

CONCENTRATION PROCESS.

No Drawing.

To all 11 ham it may concern:

Be it known that I, WALTER A. Soorr,

a citizen of the United States, residing at Chicago, in the county ofCook and State of Illinois, have invented certain new and usefulImprovements in Concentration Processes, of which the following is aspecification.

My invention is an improvement in the flotation process of concentrationwherein the metalliferous mineral is separated from the gangue by meansof bubbles of air or other gas. As generally practised air is introducedinto a freely flowing ore pulp to whichsome so-called modifying'agentsuch as an oil, either animal, vegetable or mineral, or some othersubstance such as coal or Wood tar or derivatives thereof, or othersubstances either soluble or insoluble have been added in suitableproportion. The air is generally introduced into the ore pulp either bymechanical agitation, which has the effect of beating the air into thepulp, or is introduced through the porous bottom of the vessel in whichthe pulp is contained. Such processes are described in Patent No.1,022,085 granted to J. M. Hyde April 2, 1912 and in Patent No.1,201,934 granted to J. M. Gallow October 17, 1916.

In practising the flotation process as above referred to it is necessarythat the modifying agent be disseminated through the pulp and suchdissemination has been accomplished by stirring or agitating the pulpafter the modifying agent is added.

I have discovered, however, that it is not necessary that the oil bemixed with the pulp but that the simple admixture of some vaporized oilwith the air that is introduced into the pulp effects the desiredconcentration. In using the term oil I include the various ire-agentswhich have been used for the purpose of causing the gaseous bubbles tohave a selective attraction for the metalliferous mineral particles asdistinguished from the particles of the gangue. I have now furtherdiscovered that it is not necessary to use any oils whatever in .theprocess, that is, it is not necessary to use any of the liquidsubstances heretofore employed in the flotation process, but that theconcentration of the ore can be eflected by the use of an admixtureofair with a permanent gas. I use the term permanent Specification ofLetters Patent.

Patented Apr. 2, 191%.,

Application filed August 27, 1917. Serial No. 188,310.

gas in the ordinarily accepted meaning of a substance that remainsgaseous under ordinary conditions as opposed to vapors which condense atordinarytemperatures' By ordmary temperatures I mean the ordinarytemperatures of'the atmosphere and of the pulp which is subjected to theprocess. I

have found that it is not necessary to conduct the process with gasesthat will condense under the conditions prevailing in the practice ofthe process, and that it is not necessary to depend upon such a relationbetween the liquefying point of the gas and the temperature of the airor pulp as will cause the gas to assume a liquid form. On the contrary,permanent gases which persist in the gaseous form at the prevailingtemperature of the atmosphere and the pulp are effective in carrying outthe flotation process. 7

For instance, a mixture of such a permanent gas with air when introducedinto the ore pulp, either by the mechanical agitation method set forthin the Hyde patent above referred to, or when introduced into the pulpthrough a porous wall of the containing vessel, will effectconcentration, causing the metalliferous mineral particles to adhere tothe bubbles and to be by them separated from the remainder of the pulp.For this purpose I prefer to utilize some hydrocarbon gas, such asmethane, or ordinary illuminating or fuel gas, but the choice of theparticular gas to be used will, of course, depend upon the availabilityof different gases and their efficiency in connection with theparticular ore to which the process is applied.

While the precise forces upon which the operation of my improvedinvention depends cannot be stated with absolute certainty, it appearsmost probable from such investigations as have been made with the apermanent gas which is mixed with the air,

, menace of permanent gases leads strongly to the conclusion. that thephenomenon depends upon adsorption. The viscous film thus formed at theinterface likewise through the force of adsorption holds themetalliferous mineral particles as distinguished from the gangueparticles, there being an attractive force due to adsorption between theviscous film and the metalliterous mineral. particles, whereas no suchforce exists between the viscous him and the gangue particles. "Whilethis explanation is offered tentatively, it seems to afford the besttheory now known and the one which best harmonizes with the facts.

The use of a permanent gas, as above described, is not dependent uponany articular method of carrying out the otation process, but, on thecontrary, is applicable for use in connection with any of the variousmodes in which flotation has heretofore been. practised.

An example of the use of my improved process is the use of a mixture ofacetylene and air used for the treatment of the zinc ore of the Butte &Superior Mining Compa'ny at Butte, Montana. In this operation a mixtureof air and acetylene was supplied to the pulp through the porous bottomof the containing vessel with the result that the gaseous bubbles risingthrough the pulp efiected concentration of the ore, the part1- cles ofzinc sulfid adhering to the bubbles and being by them carried to thesurface in the form of a layer or column of bubbles which was overflowedfrom the vessel in the usual manner. By this means the ore waseficiently concentrated. The gas used, acetylene, is a permanent gas inthe sense in which I herein use that term. The critical temperature ofacetylene is about 37 degrees centigrade, the various authoritiesvarying not over a fraction of a degree in their statements of thistemperature. The critical pressure of acetylene is about 68 atmospheres,although the statements of this figure as given by different authoritiesvary to the extent of several atmospheres. The boiling point ofacyleneat atmospheric pressure is in the ighbbrhood of -83 degrees centigrade,in authorities varying in the statement of! this figure only to theextent of a fractipn of a degree. .It will be apparent, theref re, thatunder the conditions of temper ture and pressure prevailingin ore concntration operations, acetylene is a perma ent gas and is not subjectedto conditions i temperature or pressure that would ca se it to" condenseto liquid form. It .is or this reason that I bove referred to adsorptionas the most probable explanation the results obtained in practismg myinvention.

The selection of the'particular permanent gas to be used in practisingmy invention being and the particular amount thereof to be used inadmixture with air are, of course, dependent upon the nature of the orepulp treated. The proper regulation of these factors, that is, the mostadvantageous amount of the most efficient gas, or mixture of gases inadmixture with air, can readily be determined by experimental operationsupon any given ore, such experimental operations being necessary in theapplication of any process. My invention, therefore, includes the use ofany one or more permanent gases in admixture with air and the adjustmentof such mixture as to proportions of the different ingredients in suchmanner as to efiect the best result in the separation of themetalliterous constituent of an ore, or of one or more metalliferousconstituent of an ore from the other constituents. My invention furtherincludes the use of permanent gases in connection with the several modesof procedure such agitation and by introducing the gas through a porousmedium into the pulp with resulting flotation of the metalliferousmineral, or without floating the metalliferous mineral, but merelytransporting it by means of the bubbles to a segregated portion of thepulp where the bubbles arebroken and their burden of metalliferousmineral permitted to settle. In the method last referred to the bubblesare broken as soon as they reach the surface either by means ofpulsations of gas pressure above the surface of the pulp, by mechanicalmeans, by a water spray or other convenient devices, and the bubblesuponbeing broken release the metalliferous mineral adhering to them,permitting it to settle. The operation is conducted in a vessel of suchform that the bubbles in rising are deflected to a point outside of themain current of pulp flowing through the vessel whereby the mineralfalling from the broken bubbles settles and is collected separately fromthe main stream of pulp flowing through the vessel.

Among the gases and gas mixtures which may be used are not only variousgases which are chemical compounds, but also elementary gases andmixtures of the same.

'While I have herein referred to admixtures of various permanent gaseswith air it will be obvious that the use of air is not indispensableinasmuch as other inert gases might be used in admixture with thepermanent gases herein referred to, or such permanent gases or mixturesof them might be used under some conditions without any admixture ofair, carbon dioxid or similar narily air, whose prin pal function isthat menace of furnishing the larger part of the volume of the bubbleswhile being. relativel inert in the matter of impartingto the ubbles therequired degree of persistence and selective attraction formetalliferous mineral. Of course the word inert as used in the claimsdoes not necessarily mean absolutely inert in the matter of theproperties mentioned as under some conditions )ure air bubbles may havesome degre of se lcctivity and of course all bubbles have some degree ofpersistence. The bubble-modifying gas referred to in the claims is gasthat in a practical and efficient degree imparts to the bubbles thenecessary selectivity and per-- sistence. I

While my invention in its broad aspect is not restricted to any,particular procedure for the introduction of the gaseous mixture intothe pulp, or to any particular method of collecting the mineral thatadheres to the bubbles, I have heretofore found it advantageous tointroduce the gaseous mixture into the pulp through a porous mediumthereby causing the building up of a column of bubbles and overflowingthe upper part of the bubble column as in the process set forth in theCallow patent hereinbefor referred to.

What I claim is:

1. An ore concentration process comprising the operations of forming amixture of an inert bubble-forming gas with a perma nentbubble-modifying gas which when the mixture is introduced into a body ofore pulp causes the formation above the normal pulp level of a massofbubbles to which certain of the mineral particles in the pulp adhereand others do not, introducing the mixture into an ore pulp, andseparating the mineral adhering to the bubbles so formed from theremainder of the ore.

2. An ore concentration process comprising the operations of forming amixture of an inert bubble-formin gas with a permanent bubble-modifyinggas distilled from a non-gaseous substance which when the mixture isintroduced into a body of ore pulp causes the formation above the normalpulp level of a mass of bubbles to which certain of the mineralparticles in the pulp adhere and others do not, introducing the mixtureinto an ore pulp, and separating the mineral adhering to the bubbles soformed from the remainder of the ore.

3. An ore concentration process comprising the operations of forming amixture of an inert bubble-forming gas with a perma nentbubble-modifying gas distilled from an organic compound which when themixture is introduced into a body of orepulp causes the formation abovethe normal pulp level" of a mass of bubbles to which certain of themineral particles in the pulp adhere and others do not, introducing themixture into nent bubble-modifying an ore pulp and separating themineral adhering to t e bubbles so formed from the remainder of the ore.

. 4. An ore concentration-process comprising the operations of forming amixture of an inert bubble-forming gas with a permagas which when themixture is introduced into a body of ore pulp causes the formation abovethe normal pulp level of amass of bubbles to which certain of themineral particles in the pulp adhere and others do not, introducing themixture into an orc pulp unmodified as to bubble forming tension, andseparating thcmineral adhering to the bubbles so formed from theremainder of the ore.

5. In a process of concentrating ores the operations of forming amixture of an inert bubble-forming gas with a permanent bubble-modifyinggas which when the mixture is introduced into an ore pulp causes theformation of a bubble column consisting of bubbles to which certain ofthe mineral particles in the pulp adhere and others do not, introducingsaid mixture into an ore pulp, causing the formation of a column ofbubbles above the pulp, and separating the mineral adhering to thebubbles in the upper part of the bubble column from the remainder of theore.

6. In a process of concentrating ores the operations of forming amixture of an inert bubble-forming gas with a permanent bub-'ble-modifying gas distilled from a non-gaseous substance which when themixture is introduced into an ore pulp causes the formation of a bubblecolumn consisting of bubbles to which certain of the mineral particlesin the pulp adhere and others do not, introducing said mixture into anore pulp, causing the formation of a column of bubbles above the pulp,and separating the mineral adhering to the bubbles in the upper part ofthe bubble column from the remainder of the ore.

7. In a process of concentrating ores the operations of forming amixture of an inert bubble-forming gas with a permanent bubble-modifyinggas distilled from an organic compound which when the mixture isintroduced into an ore pulp causes the formation of a bubble columnconsisting of bubbles to which certain of the mineral particles in thepulp adhere and others do not, introducing said mixture into an orepulp, causing the formation of a column of bubbles above the pulp, andseparating the mineral adhering to the bubbles in the upper part of thebubbubbles to which certain of the mineral particles in the pulp adhereand others do not, introducing said mixture into an ore pulp unmodifiedas to bubble forming tension, causing the formation of a colunm ofbubbles above the pulp, and separating the mineral adhering to thebubbles in the upper part of the bubble column from the rernainder ofthe ore.

9. In a process of concentrating ores the operations of forming amixture of an inert bubble-forming gas with a permanent bubble-modifyinggas which when the mixture is introduced into an ore pulp causes theformation of a bubble column consisting of bubbles to which certain ofthe mineral particles in the pulp adhere and others do not, introducingsaid mixture through a porous medium into an ore pulp, causing theformation of a column of bubbles above the pulp,

memos andseparating the mineral adhering to the bubbles in the upper artof the bubble column from the remain or of the ore.

10. In a process ofconcentrating ore in the form of a pump unmodified asto bubbleforming tension and contained in a vessel open to theatmosphere and having walls extendin operations of introducing mto saidpulp through a porous medium a permanent gas which when so introducedcauses the formation of a bubble column consisting of bubbles my name.

WALTER A. soo'r'r.

above the normal pulp level, the

